WALLER COUNTY, TEXAS - Video from a police dashboard camera shows how a routine traffic stop escalated into a shouting confrontation between a Texas state trooper and a woman who was later found dead in a jail cell in Waller County, Texas.

Sandra Bland, 28, of Chicago was stopped for a minor traffic violation July 10 and was arrested for assaulting an officer. Three days later, she was found dead in her jail cell, and relatives, friends and civil rights activists continue to demand an outside investigation of what happened.

The dashboard video was posted by the Texas Department of Public Safety on its website Tuesday.  After the trooper hands Bland a ticket, he tells her she seems irritated. Bland replies that she is irritated because she changed lanes to make way for the trooper’s car.

The confrontation heats up from there. Bland loudly accuses the officer of slamming her head into the ground, “all for a traffic signal!” But the encounter is off camera.

“It was not a model traffic stop, and it was not a model person that was stopped,” Waller County District Attorney Elton Mathis said at an earlier press conference.

Also Tuesday, the Waller County sheriff’s office released three hours of video from a jail camera that shows the area outside the cell where Bland died.

In that video, there is no direct view of Bland in her cell, but it does show the moment a guard discovers something is wrong. Later, paramedics arrive to remove the body.

Waller County Sheriff’s Department Captain Brian Cantrell said guards found her in a standing position with a cord fashioned from a plastic garbage bag around her neck.

“She passed through asphyxiation, so that tells you that she could not breathe, and that can happen whether standing, kneeling down or sitting down,” Cantrell said.

Mathis said final judgment on what happened to Bland would depend on evidence gathered by law enforcement authorities, including the FBI.

“It is very much too early to make any kind of determination that this was a suicide or a murder because the investigations are not complete,” Mathis said.

Bland was an outspoken critic of police abuse of African-Americans, so many in Waller County think that might have been why she was stopped.

Black religious figures have called for a Justice Department investigation, saying Bland's civil rights were violated because of her race.

Among those holding a daily vigil outside the jail is the Reverend Hannah Bonner, who identifies with Bland as a fellow activist.

“There’s that sense of solidarity that you build within the movement and that sense that we have lost one of our own,” Bonner said.

Brandi, another vigil participant, also believes racism was behind the jail cell death. “It is a tragedy for this town, for this city, for our nation that these types of brutalities continue to happen,” she said.

Officials are calling for patience as they await the results of the investigation. Those results should be known by sometime next month.